U.S. patent application number 16/099725 was filed with the patent office on 2019-05-23 for vehicle control system, vehicle control method and vehicle control program.
The applicant listed for this patent is HONDA MOTOR CO., LTD.. Invention is credited to Yoshihiro Oniwa, Mineyuki Yoshida.
Application Number | 20190155293 16/099725 |
Document ID | / |
Family ID | 60325911 |
Filed Date | 2019-05-23 |
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United States Patent
Application |
20190155293 |
Kind Code |
A1 |
Oniwa; Yoshihiro ; et
al. |
May 23, 2019 |
VEHICLE CONTROL SYSTEM, VEHICLE CONTROL METHOD AND VEHICLE CONTROL
PROGRAM
Abstract
A vehicle control system includes a position recognition part
that recognizes a vehicle position, a trajectory generating part
that generates a trajectory including future target positions to be
reached by the vehicle, the future target positions being
consecutively aligned in time series, a calculation reference
position setting part that sets a calculation reference position at
a position closest to the vehicle position in the trajectory, and a
travel controller that extracts a first target position
corresponding to a future time after a first predetermined time has
elapsed from a recognition time at which a recognition of the
position of the vehicle has been performed from among the plurality
of target positions included in the trajectory, and that derives a
target speed when the vehicle is caused to travel along the
trajectory on the basis of a length of the trajectory from the
calculation reference position to the first target position.
Inventors: |
Oniwa; Yoshihiro; (Wako-shi,
JP) ; Yoshida; Mineyuki; (Wako-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HONDA MOTOR CO., LTD. |
Minato-ku, Tokyo |
|
JP |
|
|
Family ID: |
60325911 |
Appl. No.: |
16/099725 |
Filed: |
May 1, 2017 |
PCT Filed: |
May 1, 2017 |
PCT NO: |
PCT/JP2017/017149 |
371 Date: |
November 8, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60W 2720/10 20130101;
G05D 1/0231 20130101; B60W 30/143 20130101; G01C 21/20 20130101;
B60W 60/0021 20200201; B60W 2556/50 20200201; B60W 2050/0008
20130101; G05D 1/0223 20130101; B60W 50/0097 20130101; G01C 21/3658
20130101; B60W 30/10 20130101; G01C 21/26 20130101; B60W 2050/0095
20130101; G01C 21/3629 20130101; G05D 2201/0213 20130101 |
International
Class: |
G05D 1/02 20060101
G05D001/02; G01C 21/20 20060101 G01C021/20 |
Foreign Application Data
Date |
Code |
Application Number |
May 16, 2016 |
JP |
2016-098049 |
Claims
1.-9. (canceled)
10. A vehicle control system comprising: a position recognition
part that recognizes a position of a vehicle; a trajectory
generating part that generates a trajectory which includes a
plurality of future target positions to be reached by the vehicle,
the plurality of future target positions being consecutively
aligned in time series; a calculation reference position setting
part that sets a calculation reference position at a position
closest to the position of the vehicle recognized by the position
recognition part in the trajectory; and a travel controller that
extracts a first target position corresponding to a future time
after a first predetermined time has elapsed from a recognition
time at which a recognition of the position of the vehicle has been
performed from among the plurality of target positions included in
the trajectory, and that derives a target speed when the vehicle is
caused to travel along the trajectory on the basis of a length of
the trajectory from the calculation reference position to the first
target position.
11. The vehicle control system according to claim 10, wherein the
calculation reference position setting part sets the calculation
reference position in the case of a low-speed traveling in which a
speed of the vehicle is equal to or lower than a threshold
value.
12. The vehicle control system according to claim 10, wherein the
calculation reference position setting part sets the calculation
reference position when the position of the vehicle is separated a
predetermined distance or more from the trajectory.
13. The vehicle control system according to claim 10, wherein the
travel controller corrects the derived target speed on the basis of
a first deviation between the calculation reference position and
the position of the vehicle.
14. The vehicle control system according to claim 10, wherein the
travel controller further corrects the target speed on the basis of
a second deviation between a second target position corresponding
to a future time after a second predetermined time shorter than the
first predetermined time has elapsed from the recognition time and
a predicted position that the vehicle is predicted to reach at the
future time by starting traveling of the vehicle from the
calculation reference position.
15. The vehicle control system according to claim 10, further
comprising an automated driving controller that executes any one of
a plurality of driving modes including automated driving mode in
which at least speed control of the vehicle is automatically
performed and a manual driving mode in which both the speed control
and a steering control of the vehicle are performed on the basis of
an operation of an occupant of the vehicle, wherein the travel
controller performs the speed control of the vehicle according to
the target speed when the automated driving mode is executed by the
automated driving controller.
16. The vehicle control system according to claim 15, wherein the
automated driving mode includes a plurality of modes in which
degrees of surrounding monitoring obligations of the vehicle are
different, and the automated driving controller changes the
automated driving mode to be executed to a mode in which a degree
of an automated driving is low in the case of a low-speed traveling
in which the speed of the vehicle is equal to or lower than a
threshold value or in a case in which the position of the vehicle
is separated a predetermined distance or more from the
trajectory.
17. A vehicle control method comprising: recognizing, by an
in-vehicle computer, a position of a vehicle; generating, by the
in-vehicle computer, a trajectory which includes a plurality of
future target positions to be reached by the vehicle, the plurality
of future target positions being consecutively aligned in time
series; setting, by the in-vehicle computer, a calculation
reference position at a position closest to the recognized position
of the vehicle in the trajectory; extracting, by the in-vehicle
computer, a first target position corresponding to a future time
after a first predetermined time has elapsed from a recognition
time at which a recognition of the position of the vehicle has been
performed from among the plurality of target positions included in
the trajectory; and deriving, by the in-vehicle computer, a target
speed when the vehicle is caused to travel along the trajectory on
the basis of a length of the trajectory from the calculation
reference position to the first target position.
18. A vehicle control program causing an in-vehicle computer to:
recognize a position of a vehicle; generate a trajectory which
includes a plurality of future target positions to be reached by
the vehicle, the plurality of future target positions being
consecutively aligned in time series; set a calculation reference
position at a position closest to the recognized position of the
vehicle in the trajectory; extract a first target position
corresponding to a future time after a first predetermined time has
elapsed from a recognition time at which a recognition of the
position of the vehicle has been performed from among the plurality
of target positions included in the trajectory; and derive a target
speed when the vehicle is caused to travel along the trajectory on
the basis of a length of the trajectory from the calculation
reference position to the first target position.
Description
TECHNICAL FIELD
[0001] The present invention relates to a vehicle control system, a
vehicle control method, and a vehicle control program.
[0002] Priority is claimed on Japanese Patent Application No.
2016-098049, filed May 16, 2016, the content of which is
incorporated herein by reference.
BACKGROUND ART
[0003] In the related art, a system that performs speed control or
steering control of a host vehicle on the basis of a travel locus
of a preceding vehicle is known. This system performs speed control
for the host vehicle on the basis of a difference between a target
inter-vehicle distance and an inter-vehicle distance between the
host vehicle and the preceding vehicle, and a speed difference
between the preceding vehicle and the host vehicle when the host
vehicle travels for a predetermined time (see, for example, Patent
Literature 1).
CITATION LIST
Patent Literature
[Patent Literature 1]
[0004] Japanese Unexamined Patent Application, First Publication
No. H10-100738
SUMMARY OF INVENTION
Technical Problem
[0005] However, in the related art, when a vehicle deviates from a
trajectory expressing a travel locus, speed control cannot be
appropriately performed in some cases.
[0006] An aspect of the present invention is to provide a vehicle
control system, a vehicle control method, and a vehicle control
program capable of accurately performing speed control of a vehicle
along a trajectory.
[0007] (1) A vehicle control system according to an aspect of the
present invention includes: a position recognition part that
recognizes a position of a vehicle; a trajectory generating part
that generates a trajectory which includes a plurality of future
target positions to be reached by the vehicle, the plurality of
future target positions being consecutively aligned in time series;
a calculation reference position setting part that sets a
calculation reference position at a position closest to the
position of the vehicle recognized by the position recognition part
in the trajectory; and a travel controller that extracts a first
target position corresponding to a future time after a first
predetermined time has elapsed from a recognition time at which a
recognition of the position of the vehicle has been performed from
among the plurality of target positions included in the trajectory,
and that derives a target speed when the vehicle is caused to
travel along the trajectory on the basis of a length of the
trajectory from the calculation reference position to the first
target position.
[0008] (2) In the aspect (1), the calculation reference position
setting part may set the calculation reference position in the case
of a low-speed traveling in which a speed of the vehicle is equal
to or lower than a threshold value.
[0009] (3) In the aspect (1) or (2), the calculation reference
position setting part may set the calculation reference position
when the position of the vehicle is separated from the trajectory
by a predetermined distance or more.
[0010] (4) In the aspect of any one of (1) to (3), the travel
controller may correct the derived target speed on the basis of a
first deviation between the calculation reference position and the
position of the vehicle.
[0011] (5) In the aspect of any one of (1) to (4), the travel
controller may further correct the target speed on the basis of a
second deviation between a second target position corresponding to
a future time after a second predetermined time shorter than the
first predetermined time has elapsed from the recognition time and
a predicted position that the vehicle is predicted to reach at the
future time by starting traveling of the vehicle from the
calculation reference position.
[0012] (6) In the aspect of any one of (1) to (5), the vehicle
control system may further include an automated driving controller
that executes any one of a plurality of driving modes including
automated driving mode in which at least speed control of the
vehicle is automatically performed and a manual driving mode in
which both the speed control and a steering control of the vehicle
are performed on the basis of an operation of an occupant of the
vehicle, wherein the travel controller may perform the speed
control of the vehicle according to the target speed when the
automated driving mode is executed by the automated driving
controller.
[0013] (7) In the aspect (6), the automated driving mode may
include a plurality of modes in which degrees of surrounding
monitoring obligations of the vehicle are different, and the
automated driving controller may change the mode to be executed to
a mode in which the degree of the surrounding monitoring obligation
is low in the case of a low-speed traveling in which the speed of
the vehicle is equal to or lower than a threshold value or in a
case in which the position of the vehicle is separated from the
trajectory by a predetermined distance or more.
[0014] (8) A vehicle control method according to an aspect of the
present invention may include recognizing, by an in-vehicle
computer, a position of a vehicle; generating, by the in-vehicle
computer, a trajectory which includes a plurality of future target
positions to be reached by the vehicle, the plurality of future
target positions being consecutively aligned in time series;
setting, by the in-vehicle computer, a calculation reference
position at a position closest to the recognized position of the
vehicle in the trajectory; extracting, by the in-vehicle computer,
a first target position corresponding to a future time after a
first predetermined time has elapsed from a recognition time at
which a recognition of the position of the vehicle has been
performed from among the plurality of target positions included in
the trajectory; and deriving, by the in-vehicle computer, a target
speed when the vehicle is caused to travel along the trajectory on
the basis of a length of the trajectory from the set calculation
reference position to the extracted target position.
[0015] (9) A vehicle control program according to an aspect of the
present invention causes an in-vehicle computer to: recognize a
position of a vehicle; generate a trajectory which includes a
plurality of future target positions to be reached by the vehicle,
the plurality of future target positions being consecutively
aligned in time series; set a calculation reference position at a
position closest to the recognized position of the vehicle in the
trajectory; extract a first target position corresponding to a
future time after a first predetermined time has elapsed from a
recognition time at which a recognition of the position of the
vehicle has been performed from among the plurality of target
positions included in the trajectory; and derive a target speed
when the vehicle is caused to travel along the trajectory on the
basis of a length of the trajectory from the calculation reference
position to the first target position.
Advantageous Effects of Invention
[0016] According to the above aspects (1) to (9), it is possible to
accurately perform the speed control of the vehicle along the
trajectory.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1 is a figure illustrating components of a host vehicle
in which a vehicle control system according to each embodiment is
mounted.
[0018] FIG. 2 is a functional configuration figure having a vehicle
control system according to a first embodiment in the center.
[0019] FIG. 3 is a figure illustrating a state in which a relative
position of the host vehicle with respect to a travel lane is
recognized by a host vehicle position recognition part.
[0020] FIG. 4 is a figure illustrating an example of an action plan
generated for a certain section.
[0021] FIG. 5 is a figure illustrating an example of a
configuration of a trajectory generating part.
[0022] FIG. 6 is a figure illustrating an example of a trajectory
candidate generated by a trajectory candidate generation part.
[0023] FIG. 7 is a figure in which candidates for a trajectory
generated by the trajectory candidate generation part are
represented by trajectory points.
[0024] FIG. 8 is a figure illustrating a lane change target
position.
[0025] FIG. 9 is a figure illustrating a speed generation model in
a case the speeds of three nearby vehicles are assumed to be
constant.
[0026] FIG. 10 is a figure illustrating an example of operation
allowability information corresponding to a control mode.
[0027] FIG. 11 is a figure illustrating a relationship between a
steering controller/an acceleration and deceleration controller and
a control target thereof.
[0028] FIG. 12 is a figure illustrating an example of a
configuration of the acceleration and deceleration controller in
the first embodiment.
[0029] FIG. 13 is a flowchart showing an example of a flow of a
process of the acceleration and deceleration controller in the
first embodiment.
[0030] FIG. 14 is a figure illustrating an example of a
configuration of an acceleration and deceleration controller
according to a second embodiment.
[0031] FIG. 15 is a figure illustrating an example of a first dead
zone with respect to a current deviation.
[0032] FIG. 16 is a figure illustrating another example of the
first dead zone with respect to the current deviation.
[0033] FIG. 17 is a figure illustrating an example of a second dead
zone with respect to a future deviation.
[0034] FIG. 18 is a figure illustrating another example of the
second dead zone with respect to the future deviation.
[0035] FIG. 19 is a figure illustrating an example of acceleration
and deceleration control in each situation.
[0036] FIG. 20 is a figure illustrating still another example of
the first dead zone with respect to the current deviation.
[0037] FIG. 21 is a figure illustrating still another example of
the first dead zone with respect to the current deviation.
[0038] FIG. 22 is a figure illustrating still another example of
the second dead zone with respect to the future deviation.
[0039] FIG. 23 is a figure illustrating still another example of
the second dead zone with respect to the future deviation.
[0040] FIG. 24 is a figure illustrating an example of acceleration
and deceleration control in each situation.
[0041] FIG. 25 is a figure illustrating a method of changing an
area size of a dead zone.
[0042] FIG. 26 is a figure illustrating a method of changing the
area size of the dead zone.
[0043] FIG. 27 is a flowchart showing an example of a flow of a
process of the acceleration and deceleration controller in the
second embodiment.
[0044] FIG. 28 is a figure illustrating an example of a
configuration of an acceleration and deceleration controller in a
third embodiment.
[0045] FIG. 29 is a figure illustrating an example of change in
output gain with respect to a speed of a host vehicle.
[0046] FIG. 30 is a figure illustrating an example of a
configuration of an acceleration and deceleration controller in a
fourth embodiment.
[0047] FIG. 31 is a figure illustrating a method of setting a
calculation reference position.
[0048] FIG. 32 is a figure schematically illustrating an example of
correction of the calculation reference position.
[0049] FIG. 33 is a figure schematically illustrating another
example of the correction of the calculation reference
position.
[0050] FIG. 34 is a flowchart showing an example of a flow of a
process of a fifth calculation part in the fourth embodiment.
[0051] FIG. 35 is a figure illustrating an example of a
configuration of an acceleration and deceleration controller in the
fifth embodiment.
DESCRIPTION OF EMBODIMENTS
[0052] Hereinafter, embodiments of a vehicle control system, a
vehicle control method, and a vehicle control program of the
present invention will be described with reference to the
drawings.
[0053] [Common Configuration]
[0054] FIG. 1 is a figure illustrating components included in a
vehicle on which a vehicle control system 100 of each embodiment is
mounted (hereinafter referred to as a host vehicle M). The vehicle
on which the vehicle control system 100 is mounted is, for example,
a two-wheeled vehicle, a three-wheeled vehicle, or a four-wheeled
vehicle, and includes a vehicle using an internal combustion engine
such as a diesel engine or a gasoline engine as a power source, an
electric vehicle using an electric motor as a power source, a
hybrid vehicle with an internal combustion engine and an electric
motor, and the like. Further, the electric vehicle is driven, for
example, using electric power that is discharged by a battery such
as a secondary battery, a hydrogen fuel cell, a metal fuel cell, or
an alcohol fuel cell.
[0055] As illustrated in FIG. 1, sensors such as finders 20-1 to
20-7, radars 30-1 to 30-6, and a camera 40, a navigation device 50
(a route guidance device), and the vehicle control system 100 are
mounted on the host vehicle M.
[0056] The finders 20-1 to 20-7 are, for example, light detection
and ranging or laser imaging detection and ranging (LIDAR) finders
that measure scattered light with respect to irradiation light and
measures a distance up to a target. For example, the finder 20-1
may be attached to a front grille or the like, and the finders 20-2
and 20-3 may be attached to a side surface of a vehicle body, a
door mirror, the inside of a headlight, the vicinity of side lamps,
and the like. The finder 20-4 is attached to a trunk lid or the
like, and the finders 20-5 and 20-6 are attached to the side
surface of the vehicle body, the inside of a taillight, or the
like. The finders 20-1 to 20-6 described above have, for example, a
detection area of about 150.degree. in a horizontal direction.
Further, the finder 20-7 is attached to a roof or the like.
[0057] The finder 20-7 has, for example, a detection area of
360.degree. in the horizontal direction.
[0058] The radars 30-1 and 30-4 are, for example, long-distance
millimeter-wave radars of which the detection area in a depth
direction is wider than those of other radars. Further, the radars
30-2, 30-3, 30-5, and 30-6 are intermediate-distance millimeter
wave radars of which the detection area in the depth direction is
narrower than those of the radars 30-1 and 30-4.
[0059] Hereinafter, the finders 20-1 to 20-7 are simply referred to
as a "finder 20" when not particularly distinguished, and the
radars 30-1 to 30-6 are simply referred to as a "radar 30" when not
particularly distinguished. The radar 30 detects an object using,
for example, a frequency modulated continuous wave (FM-CW)
scheme.
[0060] The camera 40 is, for example, a digital camera using a
solid-state imaging element such as a charge coupled device (CCD)
or a complementary metal oxide semiconductor (CMOS). The camera 40
is attached to an upper portion of a front windshield, a rear
surface of a rearview mirror, or the like. The camera 40
periodically and repeatedly images, for example, in front of the
host vehicle M. The camera 40 may be a stereo camera including a
plurality of cameras.
[0061] It should be noted that the configuration illustrated in
FIG. 1 is merely an example, and a part of the configuration may be
omitted or other components may be added.
First Embodiment
[0062] FIG. 2 is a functional configuration figure having a vehicle
control system 100 according to a first embodiment in the
center.
[0063] A detection device DD including the finder 20, the radar 30,
the camera 40, and the like, the navigation device 50, a
communication device 55, a vehicle sensor 60, a display device 62,
a speaker 64, a content reproduction device 66, an operation device
70, an operation detection sensor 72, a changeover switch 80, a
vehicle control system 100, a driving force output device 200, a
steering device 210, and a brake device 220 are mounted in the host
vehicle M.
[0064] These apparatuses or devices are connected to each other by
a multiplex communication line such as a controller area network
(CAN) communication line, a serial communication line, a wireless
communication network, or the like. It should be noted that a
vehicle control system in the claims does not refer to only the
"vehicle control system 100" and may include a configuration (for
example, the detection device DD) other than the vehicle control
system 100.
[0065] The navigation device 50 includes a global navigation
satellite system (GNSS) receiver or map information (navigation
map), a touch panel type display device functioning as a user
interface, a speaker, a microphone, and the like. The navigation
device 50 specifies a position of the host vehicle M using the GNSS
receiver and derives a route from the position to a destination
designated by the user.
[0066] The route derived by the navigation device 50 is provided to
the target lane determination part 110 of the vehicle control
system 100. The position of the host vehicle M may be specified or
supplemented by an inertial navigation system (INS) using the
output of the vehicle sensor 60.
[0067] Further, when the vehicle control system 100 is executing a
manual driving mode, the navigation device 50 performs guidance
through sound or a navigation display for the route to the
destination.
[0068] It should be noted that a configuration for specifying the
position of the host vehicle M may be provided independently of the
navigation device 50.
[0069] Further, the navigation device 50 may be realized, for
example, by a function of a terminal device such as a smartphone or
a tablet terminal possessed by the user. In this case, transmission
and reception of information is performed between the terminal
device and the vehicle control system 100 through wireless or wired
communication.
[0070] The communication device 55 performs wireless communication
using, for example, a cellular network, a Wi-Fi network, Bluetooth
(registered trademark), dedicated short range communication (DSRC),
or the like.
[0071] The vehicle sensors 60 include, for example, a vehicle speed
sensor that detects a vehicle speed, an acceleration sensor that
detects an acceleration, a yaw rate sensor that detects an angular
speed around a vertical axis, and an azimuth sensor that detects a
direction of the host vehicle M. The vehicle sensor 60 is an
example of a "detector".
[0072] The display device 62 is, for example, a liquid crystal
display (LCD) or an organic electroluminescence (EL) display device
attached to each portion of an instrument panel, any place facing a
front passenger seat or a rear seat, or the like. Further, the
display device 62 may be a head up display (HUD) that projects an
image onto a front windshield or another window. Further, the
display device 62 detects a touch operation with respect to a panel
when the display device 62 is a touch panel. The speaker 64 outputs
information as sound.
[0073] The content reproduction device 66 includes, for example, a
digital versatile disc (DVD) playing device, a compact disc (CD)
playing device, a television receiver, or a various-guidance images
generation device. Various types of content information reproduced
by the content reproduction device 66 may be output via the display
device 62 or the speaker 64.
[0074] The operation device 70 includes, for example, an
accelerator pedal, a steering wheel, a brake pedal, a shift lever,
and the like. The operation detection sensor 72 that detects the
presence or absence or the amount of an operation of the driver is
attached to the operation device 70.
[0075] The operation detection sensor 72 includes, for example, a
degree-of-accelerator opening sensor, a steering torque sensor, a
brake sensor, a shift position sensor, and the like. The operation
detection sensor 72 outputs a degree of accelerator opening, a
steering torque, a brake depression amount, a shift position, and
the like as detection results to the travel controller 160.
[0076] It should be noted that, alternatively, the detection
results of the operation detection sensor 72 may be directly output
to the driving force output device 200, the steering device 210, or
the brake device 220.
[0077] The changeover switch 80 is a switch that is operated by the
vehicle occupant. The changeover switch 80 receives an operation of
the vehicle occupant, generates a control mode designation signal
for designating a control mode of the travel controller 160 as any
one of the automated driving mode and the manual driving mode, and
outputs the control mode designation signal to the switching
controller 150.
[0078] The automated driving mode is an driving mode in which a
vehicle travels in a state in which the driver does not perform an
operation (or the amount of operation is smaller than that in the
manual driving mode or an operation frequency is low), as described
above. More specifically, the automated driving mode is a driving
mode for controlling some or all of the driving force output device
200, the steering device 210, and the brake device 220 on the basis
of an action plan.
[0079] Further, the changeover switch 80 may receive various
operations, in addition to an operation for switching the automated
driving mode. For example, when information output from the vehicle
control system 100 is presented to the vehicle occupant via the
display device 62, the changeover switch 80 may receive, for
example, a response operation with respect to this information.
[0080] The driving force output device 200, the steering device
210, and the brake device 220 will be described before the vehicle
control system 100 is described.
[0081] The driving force output device 200 outputs a travel driving
force (torque) for causing the vehicle to travel to a driving
wheel. For example, when the host vehicle M is a vehicle using an
internal combustion engine as a power source, the driving force
output device 200 includes an engine, a transmission, and an engine
electronic control unit (ECU) that controls the engine. Further,
when the host vehicle M is an electric car using an electric motor
as a power source, the driving force output device 200 includes a
traveling motor and a motor ECU that controls the traveling motor.
Further, when the host vehicle M is a hybrid vehicle, the driving
force output device 200 includes an engine, a transmission, an
engine ECU, a traveling motor, and a motor ECU.
[0082] When the driving force output device 200 includes only an
engine, the engine ECU adjusts a degree of throttle opening of
engine, a gear shift stage, and the like according to information
input from a travel controller 160 to be described below.
[0083] When the driving force output device 200 includes only a
traveling motor, the motor ECU adjusts a duty ratio of a PWM signal
to be given to the traveling motor according to the information
input from the travel controller 160.
[0084] When the driving force output device 200 includes an engine
and a traveling motor, the engine ECU and the motor ECU cooperate
with each other to control the travel driving force according to
the information input from the travel controller 160.
[0085] The steering device 210 includes, for example, a steering
ECU and an electric motor.
[0086] The electric motor, for example, changes a direction of the
steerable wheels by applying a force to a rack and pinion
mechanism.
[0087] The steering ECU drives the electric motor according to
information input from the vehicle control system 100 or input
information on the steering angle or the steering torque, to change
directions of the steerable wheels.
[0088] The brake device 220 is, for example, an electric servo
brake device including a brake caliper, a cylinder that transfers
hydraulic pressure to the brake caliper, an electric motor that
generates the hydraulic pressure in the cylinder, and a brake
controller.
[0089] The brake controller of the electric servo brake device
controls the electric motor according to information input from the
travel controller 160 so that a brake torque according to the
braking operation is output to each wheel.
[0090] The electric servo brake device may include, as a backup, a
mechanism for transferring the hydraulic pressure generated by the
operation of the brake pedal to the cylinder via a master
cylinder.
[0091] It should be noted that the brake device 220 is not limited
to the electric servo brake device described above, and may be an
electronically controlled hydraulic brake device. The
electronically controlled hydraulic brake device controls an
actuator according to the information input from the travel
controller 160 and transfers the hydraulic pressure of the master
cylinder to the cylinder.
[0092] In addition, the brake device 220 may include a regenerative
brake using a traveling motor that may be included in the driving
force output device 200. This regenerative brake uses electric
power generated by the traveling motor that may be included in the
driving force output device 90.
[0093] [Vehicle Control System]
[0094] Hereinafter, the vehicle control system 100 will be
described. The vehicle control system 100 is realized by, for
example, one or more processors or hardware having equivalent
functions. The vehicle control system 100 may have a configuration
in which, for example, a processor such as a central processing
unit (CPU), a storage device, an electronic control unit (ECU)
having a communication interface connected by an internal bus, and
a micro-processing unit (MPU) are combined.
[0095] Referring back to FIG. 2, the vehicle control system 100
includes, for example, the target lane determination part 110, an
automated driving controller 120, a travel controller 160, and a
storage 190.
[0096] The automated driving controller 120 includes, for example,
an automated driving mode controller 130, a host vehicle position
recognition part 140, an outside recognition part 142, an action
plan generating part 144, a trajectory generating part 146, and a
switching controller 150.
[0097] Target lane determination part 110, each parts of the
automated driving controller 120, and some or all of the travel
controller 160 are realized by a processor executing a program
(software). Further, some or all of the parts may be realized by
hardware such as a large scale integration (LSI) or an application
specific integrated circuit (ASIC) or may be realized in a
combination of software and hardware.
[0098] Information such as high-precision map information 192,
target lane information 194, action plan information 196, and
operation allowability information 198 corresponding to the control
mode, for example, is stored in the storage 190.
[0099] The storage 190 is realized by a read only memory (ROM), a
random access memory (RAM), a hard disk drive (HDD), a flash
memory, or the like. The program to be executed by the processor
may be stored in the storage 190 in advance or may be downloaded
from an external device via an in-vehicle Internet facility or the
like.
[0100] Further, the program may be installed in the storage 190 by
a portable storage medium having the program stored therein being
mounted on a drive device (not illustrated).
[0101] Further, the vehicle control system 100 may be distributed
by a plurality of computer devices.
[0102] The target lane determination part 110 is realized by, for
example, an MPU. The target lane determination part 110 divides the
route provided from the navigation device 50 into a plurality of
blocks (for example, divides a route every 100 [m] in a vehicle
traveling direction), and determines the target lane for each block
by referring to the high-precision map information 192. The target
lane determination part 110, for example, determines the lane from
the left in which the host vehicle is traveling. The target lane
determination part 110 determines, for example, the target lane so
that the host vehicle M can travel on a reasonable traveling route
for traveling to a branch destination when a branch place or a
merging place exists in the route. The target lane determined by
the target lane determination part 110 is stored in the storage 190
as the target lane information 194.
[0103] The high-precision map information 192 is map information
with higher precision than that of the navigation map included in
the navigation device 50. The high-precision map information 192
includes, for example, information on a center of a lane or
information on boundaries of a lane.
[0104] Further, the high-precision map information 192 may include
road information, traffic regulations information, address
information (address and postal code), facilities information,
telephone number information, and the like.
[0105] The road information includes information indicating types
of road such as expressways, toll roads, national highways, and
prefectural roads, or information such as the number of lanes on a
road, a width of each lane, a gradient of the road, a position of
the road (three-dimensional coordinates including a longitude, a
latitude, and a height), a curvature of a curve of the lane, a
position of a merging or branching point of a lane, and signs
provided on a road.
[0106] The traffic regulation information includes information such
as lane closures due to roadwork, traffic accidents, traffic
congestion, or the like.
[0107] The automated driving mode controller 130 determines an
automated driving mode to be executed by the automated driving
controller 120. The automated driving mode in the first embodiment
includes the following modes. It should be noted that the following
is merely an example, and the number of automated driving modes or
the content of the mode may be arbitrarily determined.
[0108] [Mode A]
[0109] Mode A is a mode in which a degree of automated driving is
highest. When mode A is performed, all vehicle controls such as
complicated merging control are automatically performed, and
therefore, the vehicle occupant does not have to monitor the
surroundings or a state of the host vehicle M. That is, in mode A,
the vehicle occupant does not have a surroundings monitoring
obligation.
[0110] [Mode B]
[0111] Mode B is a mode in which the degree of automated driving is
next highest after mode A. When mode B is performed, all the
vehicle controls are automatically performed in principle, but the
driving operation of the host vehicle M ma be entrusted to the
vehicle occupant according to situations. Therefore, it is
necessary for the vehicle occupant to monitor the surroundings or
state of the host vehicle M. That is, in mode B, the vehicle
occupant has the surroundings monitoring obligation.
[0112] [Mode C]
[0113] Mode C is a mode in which the degree of automated driving is
next highest after mode B. When mode C is performed, the vehicle
occupant needs to perform a confirmation operation with respect to
the changeover switch 80 according to situations. In mode C, for
example, the vehicle occupant is notified of a timing of a lane
change, and when the vehicle occupant performs an operation with
respect to the changeover switch 80 for instructing lane change,
automatic lane change is performed. Therefore, it is necessary for
the vehicle occupant to monitor the surroundings or state of the
host vehicle M. That is, in mode C, the vehicle occupant has the
surroundings monitoring obligation.
[0114] The automated driving mode controller 130 determines the
automated driving mode on the basis of an operation of the vehicle
occupant with respect to the changeover switch 80, an event
determined by the action plan generating part 144, a travel aspect
determined by the trajectory generating part 146, and the like.
[0115] The output controller 155 is notified of information on the
automated driving mode determined by the automated driving mode
controller 130. In the automated driving mode, a limit may be set
according to the performance or the like of the detection device DD
of the host vehicle M. For example, when the performance of the
detection device DD is low, mode A may not be performed.
[0116] In any of the modes, it is possible to switch the driving
mode to the manual driving mode (overriding) according to an
operation with respect to the changeover switch 80.
[0117] The host vehicle position recognition part 140 of the
automated driving controller 120 recognizes a lane (travel lane) in
which the host vehicle M is traveling, and a relative position of
the host vehicle M with respect to the travel lane on the basis of
the high-precision map information 192 stored in the storage 190,
and information input from the finders 20, the radars 30, the
camera 40, the navigation device 50, or the vehicle sensor 60.
[0118] The host vehicle position recognition part 140 compares, for
example, a pattern of a road division line (for example, an
arrangement of a solid line and a broken line) recognized from the
high-precision map information 192 with a pattern of a road
division line around the host vehicle M recognized from an image
captured by the camera 40 in order to recognize the travel
lane.
[0119] In this recognition, the position of the host vehicle M
acquired from the navigation device 50 or a processing result by an
INS may be added.
[0120] FIG. 3 is a figure illustrating a state in which the
relative position of the host vehicle M with respect to the travel
lane L1 is recognized by the host vehicle position recognition part
140. The host vehicle position recognition part 140, for example,
may recognize a deviation OS of a reference point G (for example, a
centroid) of the host vehicle M from a travel lane center CL, and
an angle .theta. with respect to a connecting line along the travel
lane center CL in the travel direction of the host vehicle M, as
the relative position of the host vehicle M with respect to the
travel lane L1.
[0121] It should be noted that, instead of this, the host vehicle
position recognition part 140 may recognize, for example, the
position of the reference point of the host vehicle M with respect
to one of side end portions of the host vehicle lane L1 as the
relative position of the host vehicle M with respect to the travel
lane. The relative position of the host vehicle M recognized by the
host vehicle position recognition part 140 is provided to the
target lane determination part 110.
[0122] The outside recognition part 142 recognizes a state such as
a position, a speed, and an acceleration of a nearby vehicle on the
basis of information input from the finder 20, the radar 30, the
camera 40, and the like.
[0123] The nearby vehicle is, for example, a vehicle that is
traveling around the host vehicle M and is a vehicle that travels
in the same direction as that of the host vehicle M. The position
of the nearby vehicle may be represented by a representative point
such as a centroid or a corner of another vehicle or may be
represented by an area represented by an outline of another
vehicle.
[0124] The "state" of the nearby vehicle may include an
acceleration of the nearby vehicle, and an indication of whether or
not the nearby vehicle is changing lane (or whether or not the
nearby vehicle is about to change lane), which are recognized on
the basis of the information of the various devices.
[0125] Further, the outside recognition part 142 may also recognize
a position of a guardrail, a utility pole, a parked vehicle, a
pedestrian, and other objects, in addition to nearby vehicles.
[0126] The action plan generating part 144 sets a starting point of
automated driving and/or a destination for automated driving. The
starting point of automated driving may be a current position of
the host vehicle M or may be a point at which an operation for
instructing automated driving is performed. The action plan
generating part 144 generates the action plan in a section between
the starting point and the destination for automated driving. It
should be noted that the present invention is not limited thereto,
and the action plan generating part 144 may generate the action
plan for any section.
[0127] The action plan includes, for example, a plurality of events
to be executed sequentially. Examples of the events include a
deceleration event for decelerating the host vehicle M, an
acceleration event for accelerating the host vehicle M, a lane
keeping event for causing the host vehicle M to travel so that the
host vehicle M does not deviate from a travel lane, a lane change
event for changing the travel lane, an overtaking event for causing
the host vehicle M to overtake a preceding vehicle, a branching
event for changing a lane to a desired lane at a branch point or
causing the host vehicle M to travel so that the host vehicle M
does not deviate from a current travel lane, a merging event for
accelerating and decelerating the host vehicle M at a merging lane
for merging into a main lane and changing the travel lane, and a
handover event in which the driving mode is shifted from the manual
driving mode to the automated driving mode at a start point of
automated driving or the driving mode is shifted from the automated
driving mode to the manual driving mode at a scheduled end point of
automated driving.
[0128] The action plan generating part 144 sets a lane change
event, a branch event, or a merging event at a place at which the
target lane determined by the target lane determination part 110 is
switched.
[0129] Information indicating the action plan generated by the
action plan generating part 144 is stored in the storage 190 as
action plan information 196.
[0130] FIG. 4 is a figure illustrating an example of an action plan
generated for a certain section. As illustrated in FIG. 4, the
action plan generating part 144 generates an action plan necessary
for the host vehicle M to travel on the target lane indicated by
the target lane information 194. It should be noted that the action
plan generating part 144 may dynamically change the action plan
according to a change in a situation of the host vehicle M
irrespective of the target lane information 194.
[0131] For example, in a case a speed of the nearby vehicle
recognized by the outside recognition part 142 exceeds a threshold
value during vehicle traveling or a moving direction of the nearby
vehicle traveling in the lane adjacent to the host vehicle lane is
directed toward the host vehicle lane, the action plan generating
part 144 changes events that have been set in driving sections in
which the host vehicle M is scheduled to travel.
[0132] For example, in a case in which an event is set so that a
lane change event is executed after a lane keeping event, when it
has been found from a result of the recognition of the outside
recognition part 142 that a vehicle has traveled at a speed equal
to or higher than a threshold value from behind in a lane that is a
lane change destination during the lane keeping event, the action
plan generating part 144 changes an event subsequent to the lane
keeping event from a lane change event to a deceleration event, a
lane keeping event, or the like. As a result, even when a change
occurs in a state of the outside, the vehicle control system 100
can cause the host vehicle M to safely automatically travel.
[0133] FIG. 5 is a figure illustrating an example of a
configuration of the trajectory generating part 146. The trajectory
generating part 146 includes, for example, a travel aspect
determination part 146A, a trajectory candidate generation part
146B, and an evaluation and selection part 146C.
[0134] For example, when a lane keeping event is performed, the
travel aspect determination part 146A determines a travel aspect of
any one of constant speed traveling, following traveling, low-speed
following traveling, decelerating traveling, curved traveling,
obstacle avoidance traveling, and the like.
[0135] In this case, when there are no other vehicles in front of
the host vehicle M, the travel aspect determination part 146A
determines the travel aspect to be the constant speed
traveling.
[0136] Further, when the vehicle is to perform following traveling
with respect to the preceding vehicle, the travel aspect
determination part 146A determines the travel aspect to be the
following traveling.
[0137] Further, the travel aspect determination part 146A
determines the travel aspect to be the low-speed follow traveling
in a congested situation or the like.
[0138] Further, when the outside recognition part 142 recognizes
deceleration of the preceding vehicle or when an event such as
stopping or parking is performed, the travel aspect determination
part 146A determines the travel aspect to be the decelerating
traveling.
[0139] Further, when the outside recognition part 142 recognizes
that the host vehicle M has reached a curved road, the travel
aspect determination part 146A determines the travel aspect to be
the curved traveling.
[0140] Further, when an obstacle is recognized in front of the host
vehicle M by the outside recognition part 142, the travel aspect
determination part 146A determines the travel aspect to be the
obstacle avoidance traveling.
[0141] Further, when a lane change event, an overtaking event, a
branch event, a merging event, a handover event, or the like is
performed, the travel aspect determination part 146A determines the
travel aspect according to each event.
[0142] The trajectory candidate generation part 146B generates
candidates for the trajectory on the basis of the travel aspect
determined by the travel aspect determination part 146A. FIG. 6 is
a figure illustrating an example of candidates for the trajectory
generated by the trajectory candidate generation part 146B. FIG. 6
illustrates candidates for the trajectory generated when the host
vehicle M changes the lane from the lane L1 to the lane L2.
[0143] The trajectory candidate generation part 146B determines the
trajectory as illustrated in FIG. 6, for example, to be a
collection of the target positions (the trajectory points K) that
the reference position G (for example, a centroid or a rear wheel
shaft center) of the host vehicle M should reach at every
predetermined future time. In the embodiment, an example in which
an interval between predetermined future times is one second will
be described.
[0144] FIG. 7 is a figure in which the candidate for the trajectory
generated by the trajectory candidate generation part 146B is
represented by the trajectory points K. When an interval between
the trajectory points K is wider, the speed of the host vehicle M
becomes higher, and when the interval between the trajectory points
K is narrower, the speed of the host vehicle M becomes lower.
Therefore, the trajectory candidate generation part 146B gradually
widens the interval between the trajectory points K when
acceleration is desired, and gradually narrows the interval between
the trajectory points K when deceleration is desired.
[0145] Thus, since the trajectory point K includes a speed
component, the trajectory candidate generation part 146B needs to
give a target speed to each trajectory point K. The target speed
may be determined according to the travel aspect determined by the
travel aspect determination part 146A.
[0146] A scheme of determining the target speed when lane change
(including branching) is performed will be described herein.
[0147] The trajectory candidate generation part 146B first sets a
lane changing target position (or a merging target position). The
lane changing target position is set as a relative position with
respect to the nearby vehicle and is used for a determination as to
"whether the lane change is performed between the host vehicle and
a certain nearby vehicle". The trajectory candidate generation part
146B determines the target speed when the lane change is performed
while focusing on three nearby vehicles with reference to the lane
changing target position. FIG. 8 is a figure illustrating the lane
changing target position TA.
[0148] In FIG. 8, L1 indicates the host vehicle traveling lane, and
L2 indicates an adjacent lane.
[0149] Here, a nearby vehicle traveling immediately in front of the
host vehicle M on the same lane as that of the host vehicle M is
referred to as a preceding vehicle mA, a nearby vehicle traveling
immediately in front of the lane changing target position TA is
referred to as a front reference vehicle mB, and a nearby vehicle
traveling immediately behind the lane changing target position TA
is referred to as a rear reference vehicle mC.
[0150] The host vehicle M needs to perform acceleration or
deceleration in order to move to the side of the lane changing
target position TA, but should avoid catching up with the preceding
vehicle mA in this case. Therefore, the trajectory candidate
generation part 146B predicts a future state of the three nearby
vehicles and determines a target speed so that the host vehicle M
does not interfere or contact with each nearby vehicle.
[0151] FIG. 9 is a figure illustrating a speed generation model
when speeds of three nearby vehicles are assumed to be constant. In
FIG. 9, straight lines extending from points mA, mB, and mC
indicate displacements in a traveling direction when each nearby
vehicle is assumed to perform constant speed traveling. The host
vehicle M should be between the front reference vehicle mB and the
rear reference vehicle mC at a point CP at which the lane change is
completed and should be behind the preceding vehicle mA before
that. Under such limitation, the trajectory candidate generation
part 146B derives a plurality of time-series patterns of the target
speed until the lane change is completed. The trajectory candidate
generation part 146B derives a plurality of trajectory candidates
as illustrated in FIG. 7 by applying the time-series patterns of
the target speed to a model such as a spline curve.
[0152] It should be noted that a motion pattern of the three nearby
vehicles is not limited to the constant speed as illustrated in
FIG. 9, but the prediction may be performed on the premise of
constant acceleration and constant jerk.
[0153] The evaluation and selection part 146C performs evaluation
on the trajectory candidates generated by the trajectory candidate
generation part 146B, for example, from two viewpoints including
planning and safety, and selects a trajectory to be output to the
travel controller 160. From the viewpoint of the planning, for
example, when follow-up of an already generated plan (for example,
the action plan) is high and a total length of the trajectory is
short, the trajectory obtains a high evaluation. For example, when
lane change to the right is desired, a trajectory in which the lane
change to the left is performed and then returning is performed
obtains a low evaluation. From the viewpoint of the safety, for
example, as a distance between the host vehicle M and an object (a
nearby vehicle or the like) is longer at each trajectory point and
the change amount in acceleration/deceleration or steering angle is
smaller, a high evaluation is obtained.
[0154] The switching controller 150 switches the driving mode
between the automated driving mode and the manual driving mode on
the basis of the signal input from the changeover switch 80.
Further, the switching controller 150 switches the driving mode
from the automated driving mode to the manual driving mode on the
basis of an operation with respect to the operation device 70 for
instructing acceleration/deceleration or steering. For example, the
switching controller 150 switches the driving mode from the
automated driving mode to the manual driving mode when a state in
which the amount of operation indicated by the signal input from
the operation device 70 exceeds a threshold value continues for a
reference time or more (overriding). Further, the switching
controller 150 may cause the driving mode to return to the
automated driving mode when no operation with respect to the
operation device 70 is detected for a predetermined time after
switching to the manual driving mode according to overriding.
[0155] When the information on the automated driving mode is
notified by the automated driving controller 120, the output
controller 155 controls a user interface device such as the
navigation device 50, the display device 62, the content
reproduction device 66, and the changeover switch 80 according to a
type of automated driving mode by referring to the operation
allowability information 198.
[0156] FIG. 10 is a figure illustrating an example of the operation
allowability information 198. The operation allowability
information 198 illustrated in FIG. 10 has a "manual driving mode"
and an "automated driving mode" as a driving mode item. In
addition, the "automated driving mode" includes, for example, "mode
A", "mode B", and "mode C" described above.
[0157] Further, the operation allowability information 198
includes, for example, a "navigation operation" that is an
operation with respect to the navigation device 50, a "content
reproduction operation" that is an operation with respect to the
content reproduction device 66, and an "instrument panel operation"
that is an operation with respect to the display device 62, as an
item of the user interface device.
[0158] The output controller 155 determines the user interface
device of which the use is permitted and the user interface device
of which the use is not permitted by referring to the operation
allowability information 198 on the basis of the information on the
mode acquired from the automated driving controller 120. Further,
the output controller 155 controls whether or not reception of an
operation with respect to the user interface device from the
vehicle occupant is allowable on the basis of a result of the
determination.
[0159] For example, when the driving mode to be executed by the
vehicle control system 100 is the manual driving mode, the vehicle
occupant operates the operation device 70 such as an accelerator
pedal, a brake pedal, a shift lever, or a steering wheel.
[0160] In addition, when the driving mode to be executed by the
vehicle control system 100 is mode B, mode C, or the like of the
automated driving mode, the vehicle occupant has a surroundings
monitoring obligation for the host vehicle M.
[0161] In such a case, in order to prevent distraction of attention
(driver distraction) due to actions (for example, an operation with
respect to the user interface device) other than driving of the
vehicle occupant, the output controller 155 performs control so
that an operation with respect to some or all of the user interface
devices is not received. In this case, in order to cause the
surroundings of the host vehicle M to be monitored, the output
controller 155 may cause the presence of vehicles around the host
vehicle M recognized by the outside recognition part 142 or states
of the nearby vehicles to be displayed as an image or the like on
the display device 62, and may cause a confirmation operation
according to a situation at the time of traveling of the host
vehicle M to be received by the navigation device 50, the display
device 62, the changeover switch 80, or the like.
[0162] Further, when the driving mode is mode A of the automated
driving mode, the output controller 155 relaxes regulation of the
driver distraction and performs control to receive the operation of
the vehicle occupant with respect to the user interface device of
which the operation has not been received.
[0163] For example, the output controller 155 causes the display
device 62 to display a video, causes the speaker 64 to output
sound, or causes the content reproduction device 66 to reproduce
content from a DVD or the like.
[0164] It should be noted that the content reproduced by the
content reproduction device 66 may include, for example, various
pieces of content regarding amusement and entertainment such as a
television program, in addition to the content stored on the DVD or
the like.
[0165] In addition, the above-described "content reproduction
operation" illustrated in FIG. 10 may mean a content operation
regarding such amusement and entertainment.
[0166] Further, when the mode transitions from mode A to mode B or
mode C, that is, when change to the automated driving mode in which
the surroundings monitoring obligation of the vehicle occupant
increases is performed, the output controller 155 causes the user
interface device to output predetermined information.
[0167] The predetermined information is information indicating that
the surroundings monitoring obligation increases or information
indicating that a degree of allowance of the operation with respect
to the user interface device is lowered (the operation is
restricted).
[0168] It should be noted that the predetermined information is not
limited thereto, and may include, for example, information for
prompting preparation for handover control.
[0169] As described above, the output controller 155, for example,
issues a warning or the like to the vehicle occupant on a
predetermined time before the driving mode transitions from mode A
to mode B or mode C described above, or before the host vehicle M
reaches a predetermined speed. Thus, it is possible to notify the
vehicle occupant that the surroundings monitoring obligation for
the host vehicle M is imposed on the vehicle occupant at an
appropriate timing.
[0170] As a result, it is possible to give a preparation period for
switching of automated driving to the vehicle occupant.
[0171] The travel controller 160 includes a steering controller 162
and an acceleration and deceleration controller 164. The travel
controller 160 controls the driving force output device 200, the
steering device 210, and the brake device 220 so that the host
vehicle M passes through the trajectory generated by the trajectory
generating part 146 at the scheduled time.
[0172] FIG. 11 is a figure illustrating a relationship between the
steering controller 162/the acceleration and deceleration
controller 164 and control targets thereof.
[0173] The steering controller 162 controls the steering device 210
on the basis of the trajectory generated by the trajectory
generating part 146 and the position of the host vehicle M (a host
vehicle position) recognized by the host vehicle position
recognition part 140. For example, the steering controller 162
determines a steering angle on the basis of information such as a
turning angle .PHI.i corresponding to the trajectory point K(i)
included in the trajectory generated by the trajectory generating
part 146, a vehicle speed (or an acceleration or a jerk) acquired
from the vehicle sensor 60, or an angular speed (a yaw rate) around
a vertical axis, and determines the amount of control of the
electric motor in the steering device 210 so that a displacement
corresponding to the steering angle is given to vehicle wheels.
[0174] The acceleration and deceleration controller 164 controls
the driving force output device 200 and the brake device 220 on the
basis of the speed v and the acceleration c of the host vehicle M
detected by the vehicle sensor 60 and the trajectory generated by
the trajectory generating part 146.
[0175] [Acceleration and Deceleration Control]
[0176] FIG. 12 is a figure illustrating an example of a
configuration of the acceleration and deceleration controller 164
in the first embodiment.
[0177] The acceleration and deceleration controller 164 includes,
for example, a first calculation part 165, a second calculation
part 166, a third calculation part 167, a fourth calculation part
168, subtractors 169 and 170, a proportional integral controller
171, a proportional controller 172, a first output adjustment part
173, a second output adjustment part 174, a third output adjustment
part 175, and adders 176 and 177.
[0178] It should be noted that some or all of these configurations
may be included in the trajectory generating part 146
(particularly, the trajectory candidate generation part 146B).
[0179] Hereinafter, processing content of each configuration in the
acceleration and deceleration controller 164 illustrated in FIG. 12
will be described with reference to a flowchart. FIG. 13 is a
flowchart showing an example of a flow of a process of the
acceleration and deceleration controller 164 in the first
embodiment. In the following description, in case of various
positions, a position on the traveling direction side of the host
vehicle M with reference to the position of the host vehicle M at a
certain point in time (for example, a current time t.sub.i) is
treated as a positive value, and a position on the side opposite to
the traveling direction is treated as a negative value.
[0180] First, the first calculation part 165 derives a target speed
when the host vehicle M is caused to travel along the trajectory
generated by the trajectory generating part 146 on the basis of a
distance between a plurality of trajectory points K included in the
trajectory. For example, the first calculation part 165 extracts
trajectory points K(i) to K(i+n) that the host vehicle M should
reach until a time of n seconds elapses from a current time t.sub.i
from among the plurality of trajectory points K included in the
trajectory, and derives an average speed by dividing a route length
of the trajectory including these trajectory points K(i) to K(i+n)
by the time of n seconds (step S100). This average speed is treated
as the target speed of the host vehicle M on the trajectory
including the trajectory points K(i) to K(i+n). The time for n
seconds is an example of a "first predetermined time".
[0181] The second calculation part 166 extracts the trajectory
point K(i) corresponding to the current time t.sub.i from among the
plurality of trajectory points K included in the trajectory
generated by the trajectory generating part 146.
[0182] The third calculation part 167 extracts the trajectory point
K(i+1) corresponding to a time t.sub.i+1 after a predetermined time
(for example, one second) shorter than the time of n seconds has
elapsed from the current time t.sub.i. The predetermined time
shorter than the time of n seconds from the current time t.sub.i is
an example of a "second predetermined time".
[0183] On the basis of a vehicle position P.sub.act(i) recognized
by the host vehicle position recognition part 140 and a speed v and
an acceleration c of the host vehicle M detected by the vehicle
sensor 60, the fourth calculation part 168 derives a predicted
position P.sub.pre(i+1) that the host vehicle M is predicted to
reach at the time after one second has elapsed from the current
time t.sub.i (step S102). For example, the fourth calculation part
168 derives the predicted position P.sub.pre(i+1) on the basis of
Equation (1) below. In the equation, t is a difference time between
the time t.sub.i and the time t.sub.i+1. That is, tin the equation
corresponds to a time interval (a sampling time) between the
trajectory points K.
[ Math . 1 ] P pre ( i + 1 ) = .alpha. 2 t 2 + vt + P act ( i ) ( 1
) ##EQU00001##
[0184] The subtractor 169 derives a deviation obtained by
subtracting the host vehicle position P.sub.act(i) from the
trajectory point K(i) extracted by the second calculation part 166
(hereinafter referred to as a current deviation) (step S104). The
subtractor 169 outputs the derived current deviation to the
proportional integral controller 171.
[0185] The current deviation is an example of a "first
deviation".
[0186] The subtractor 170 derives a deviation (hereinafter referred
to as a future deviation) obtained by subtracting the predicted
position P.sub.pre(i+1) derived by the fourth calculation part 168
from the trajectory point K(i+1) extracted by the third calculation
part 167 (Step S106). The subtractor 170 outputs the derived future
deviation to the proportional controller 172. The future deviation
is an example of a "second deviation".
[0187] The proportional integral controller 171 multiplies the
current deviation output by the subtractor 169 by a predetermined
proportional gain and also multiplies a time integral value of the
current deviation by a predetermined integral gain. The
proportional integral controller 171 adds the current deviation
multiplied by the proportional gain and the time integral value of
the current deviation multiplied by the integral gain to derive, as
the amount of operation, the amount of correction of the speed
(hereinafter referred to as a first correction amount) so that the
host vehicle M approaches the trajectory point K(i) from the host
vehicle position P.sub.act(i) (step S108). By inserting an integral
term in this way, it is possible to correct the target speed so
that the current deviation approaches zero. As a result, the
acceleration and deceleration controller 164 can cause the host
vehicle position P.sub.act(i) at the current time t.sub.i to
further approach the trajectory point K(i) which is the target
position corresponding to the current time t.sub.i.
[0188] The proportional controller 172 multiplies the future
deviation output by the subtractor 170 by a predetermined
proportional gain to derive, as the amount of operation, the amount
of correction of the speed (hereinafter referred to as a second
correction amount) so that the host vehicle M approaches the
trajectory point K(i+1) from the predicted position P.sub.pre(i+1)
at a time point after one second (step S110). Thus, the
proportional controller 172 performs proportional control in which
the future deviation including uncertain elements is allowed.
[0189] The first output adjustment part 173 is, for example, a
filter circuit that imposes a limitation on the first correction
amount derived by the proportional integral controller 171. For
example, the first output adjustment part 173 performs filtering on
the first correction amount so that the speed indicated by the
first correction amount is not increased or decreased by 15 km/h or
more (step S112).
[0190] The second output adjustment part 174 is, for example, a
filter circuit that imposes a limitation on the second correction
amount derived by the proportional controller 172. For example, the
second output adjustment part 174 performs filtering on the second
correction amount so that the speed indicated by the second
correction amount is not increased or decreased by 15 km/h or more,
similar to the first output adjustment part 173 (step S114).
[0191] It should be noted that a limit at the time of an increase
in speed and a limit at the time of a decrease may be different
from each other in one or both of a speed limit of filtering by the
first output adjustment part 173 and a speed limit of filtering by
the second output adjustment part 174.
[0192] The adder 176 adds the first correction amount adjusted by
the first output adjustment part 173 and the second correction
amount adjusted by the second output adjustment part 174, and
outputs a third correction amount obtained by adding the first and
second amounts of correction to the third output adjustment part
175.
[0193] The third output adjustment part 175 is, for example, a
filter circuit that imposes a limit on the third correction amount
output by the adder 176. For example, the third output adjustment
part 175 performs filtering on the third correction amount such
that the speed indicated by the third correction amount is not
increased or decreased by 5 km/h or more (step S116).
[0194] The adder 177 adds the third correction amount adjusted by
the third output adjustment part 175 to the average speed derived
by the first calculation part 165 to output a resultant value as a
target speed of the host vehicle M for n seconds from the current
time t.sub.i (step S118). Accordingly, the acceleration and
deceleration controller 164 determines the amounts of control of
the driving force output device 200 and the brake device 220
according to the target speed.
[0195] Through such control, it is possible to suppress frequent
occurrence of acceleration and deceleration. For example, when the
target speed is not corrected using the current deviation between
the host vehicle position P.sub.act(i) recognized by the host
vehicle position recognition part 140 and the trajectory point K(i)
corresponding to a time (a recognition time, such as the current
time t.sub.i) at which the recognition of the position of the host
vehicle M has been performed among the plurality of trajectory
points K(i+1), the target speed is corrected with only the second
correction amount, that is, the amount of correction of the speed
so that the host vehicle M approaches the trajectory point K(i+1)
from the predicted position P.sub.pre(i+1) at a point in time after
one second. In this case, there is a likelihood of occurrence of a
steady offset (a deviation) so that the vehicle always overtakes
each trajectory point K or the vehicle does not always catch up
with each trajectory point K due to a sensor error or the like. In
addition, since the target speed is corrected with only the future
deviation including uncertain elements, frequent acceleration and
deceleration may occur.
[0196] On the other hand, in the embodiment, since the target speed
is corrected by both the first correction amount and the second
correction amount using the current deviation, it is possible to
reduce an offset with respect to the trajectory point K. More
specifically, since the proportional integral controller 171
performs the time integration of the current deviation to derive
the first correction amount, the host vehicle position P.sub.act(i)
at the current time t.sub.i can further approach the trajectory
point K(i) which is the target position corresponding to the
current time t.sub.i. Further, by the proportional controller 172
performing the proportional control, it is possible to allow the
future deviation including uncertain elements to some extent. As a
result, it is possible to suppress frequent occurrence of
acceleration and deceleration.
[0197] According to the first embodiment described above, by
correcting the target speed by using the current deviation between
the host vehicle position P.sub.act(i) recognized by the host
vehicle position recognition part 140 and the trajectory point K(i)
corresponding to a time (a recognition time, such as the current
time t.sub.i) at which the recognition of the position of the host
vehicle M has been performed among the plurality of trajectory
points K, it is possible to suppress frequent occurrence of
acceleration and deceleration. As a result, it is possible to
reduce discomfort of the occupant.
[0198] Further, according to the first embodiment described above,
by correcting the target speed by using the future deviation
between the trajectory point K(i+1) corresponding to the time after
a predetermined time (for example, one second) shorter than the
time of n seconds has elapsed from the current time t.sub.i and the
predicted position P.sub.pre(i+1) that the host vehicle M is
predicted to reach at the time after one second has elapsed from
the current time t.sub.i, it is possible to further suppress the
frequent occurrence of acceleration and deceleration.
Second Embodiment
[0199] Hereinafter, a second embodiment will be described. The
second embodiment is different from the first embodiment in that a
dead zone DZ is set for any one or both of the future deviation and
the current deviation in order to suppress frequent acceleration
and deceleration. The dead zone DZ is an area provided for a
decrease in the amount of correction according to each deviation.
Hereinafter, such a difference will be mainly described.
[0200] FIG. 14 is a figure illustrating an example of a
configuration of an acceleration and deceleration controller 164A
in the second embodiment. The acceleration and deceleration
controller 164A further includes, for example, a proportional
integral gain adjustment part 180 and a proportional gain
adjustment part 181, in addition to the configuration of the
acceleration and deceleration controller 164 in the first
embodiment described above.
[0201] The proportional integral gain adjustment part 180 sets the
first dead zone DZ1 for the current deviation. When the current
deviation derived by the subtractor 169 is within the first dead
zone DZ1, the proportional integral gain adjustment part 180
decreases one or both of the proportional gain and the integral
gain in the proportional integral controller 171 as compared with a
case in which the current deviation is not within the first dead
zone DZ1. "Decrease in gain" means that a gain with a positive
value approaches zero or a negative value or that a gain with a
negative value approaches zero or a positive value.
[0202] FIGS. 15 and 16 are figures illustrating examples of the
first dead zone DZ1 with respect to the current deviation.
[0203] As in the examples illustrated in FIGS. 15 and 16, the first
dead zone DZ1 may be set only on the positive side of the current
deviation (the side on which the trajectory point K(i) is in front
of the host vehicle position P.sub.act(i)) or may be set to be
biased to the positive side.
[0204] "Biased to the positive side" means, for example, that a
centroid or the like of the area of the first dead zone DZ1 is
present on the positive side of the current deviation.
[0205] In the example of FIG. 15, an area in which the current
deviation ranges from zero to a threshold value Th1 (a positive
value) is set as the first dead zone DZ1.
[0206] Further, in the example of FIG. 16, an area from the
threshold value Th2 (a negative value) to a threshold value Th1 (a
positive value) is set as the first dead zone DZ1.
[0207] As illustrated in FIGS. 15 and 16, the proportional gain or
the integral gain is zero in the first dead zone DZ1. Therefore,
when the current deviation is in the first dead zone DZ1, the first
correction amount derived by the proportional integral controller
171 becomes zero or substantially zero.
[0208] The proportional gain adjustment part 181 sets the second
dead zone DZ2 for the future deviation. When the future deviation
derived by the subtractor 170 is within the second dead zone DZ2,
the proportional gain adjustment part 181 decreases the
proportional gain in the proportional controller 172 as compared
with a case in which the future deviation is not within the second
dead zone DZ2.
[0209] FIGS. 17 and 18 are figures illustrating other examples of
the second dead zone DZ2 with respect to the future deviation.
[0210] As in the examples illustrated in FIGS. 17 and 18, the
second dead zone DZ2 may be set only on the positive side of the
current deviation or may be set to be biased to the positive side,
similar to the first dead zone DZ1.
[0211] In the example of FIG. 17, an area in which the current
deviation ranges from zero to a threshold value Th1 (a positive
value) is set as the second dead zone DZ2.
[0212] Further, in the example of FIG. 18, an area from the
threshold value Th2 (a negative value) to a threshold value Th1 (a
positive value) is set as the second dead zone DZ2.
[0213] As illustrated in FIGS. 17 and 18, the proportional gain is
zero in the second dead zone DZ2. Therefore, when the future
deviation is within the second dead zone DZ2, the second correction
amount derived by the proportional controller 172 becomes zero or
substantially zero.
[0214] It should be noted that the first dead zone DZ1 and the
second dead zone DZ2 described above may be different in size of
the area from each other. Any one of both may be set only on the
positive side of the deviation, and the other may be set to be
biased to the positive side.
[0215] FIG. 19 is a figure illustrating an example of acceleration
and deceleration control for each situation. Part (a) of FIG. 19
shows one situation in which the current deviation is not within
the first dead zone DZ1. Further, part (b) of FIG. 19 shows one
situation in which the current deviation is within the first dead
zone DZ1.
[0216] In any of the situations, a trajectory point K(0) is located
in front of the host vehicle position P.sub.act(0) at a current
time t.sub.0. That is, the host vehicle M has not reached the
trajectory point K(0) to be reached at the current time
t.sub.0.
[0217] Therefore, the acceleration and deceleration controller 164
needs to control the driving force output device 200 to accelerate
the host vehicle M.
[0218] For example, in the situation illustrated in part (a) FIG.
19, since the current deviation is outside the first dead zone DZ1,
the first correction amount is added to the average speed, and the
host vehicle M is accelerated from the current average speed.
[0219] On the other hand, in the situation illustrated in part (b)
of FIG. 19, since the current deviation is within the first dead
zone DZ1, the first correction amount is decreased. In this case,
it becomes easy for the average speed derived by the first
calculation part 165 to be maintained without the acceleration
control being performed. Through such a process, it is possible to
suppress frequent acceleration when the host vehicle M has not
reached the trajectory point K(0).
[0220] Further, in the above-described example, the example in
which the dead zone DZ is set for the deviation when the trajectory
point K(i) is in front of the host vehicle position P.sub.act(i),
but the present invention is not limited thereto. When the
trajectory point K(i) is behind the host vehicle position
P.sub.act(i), the dead zone DZ may be set for the deviation.
[0221] FIGS. 20 and 21 are figures illustrating other examples of
the first dead zone DZ1 with respect to the current deviation.
[0222] As in the examples illustrated in FIGS. 20 and 21, the first
dead zone DZ1 may be set only on the negative side of the current
deviation (the side on which the trajectory point K(i) is behind
the host vehicle position P.sub.act(i)) or may be set to be biased
to the negative side.
[0223] In the example of FIG. 20, an area in which the current
deviation ranges from a threshold value Th3 (a negative value) to
zero is set as the first dead zone DZ1.
[0224] Further, in the example of FIG. 21, an area from the
threshold value Th3 (a negative value) to a threshold value Th4 (a
positive value) is set as the first dead zone DZ1.
[0225] FIGS. 22 and 23 are figures illustrating other examples of
the second dead zone DZ2 with respect to the future deviation.
[0226] As in the example illustrated in FIGS. 22 and 23, the second
dead zone DZ2 may be set only on the negative side of the current
deviation or may be set to be biased to the negative side.
[0227] In the example of FIG. 22, an area in which the current
deviation ranges from a threshold value Th3 (a negative value) to
zero is set as the second dead zone DZ2.
[0228] Further, in the example of FIG. 23, an area from the
threshold value Th3 (a negative value) to a threshold value Th4 (a
positive value) is set as the second dead zone DZ2.
[0229] In the above example, the first dead zone DZ1 and the second
dead zone DZ2 may be different in size of the area from each other.
Any one of both may be set only on the negative side of the
deviation and the other may be set to be biased to the negative
side.
[0230] FIG. 24 is a figure illustrating an example of acceleration
and deceleration control for each situation. Part (a) of FIG. 24
shows one situation in which the current deviation is not within
the first dead zone DZ1. Further, part (b) of FIG. 24 shows one
situation in which the current deviation is within the first dead
zone DZ1.
[0231] In any of the situations, a trajectory point K(0) is located
behind the host vehicle position P.sub.act(0) at the current time
t.sub.0. That is, the host vehicle M exceeds the trajectory point
K(0) to be reached at the current time t.sub.0. Therefore, the
acceleration and deceleration controller 164 needs to control the
driving force output device 200 to decelerate the host vehicle
M.
[0232] For example, in the situation illustrated in part (a) of
FIG. 24, since the current deviation is outside the first dead zone
DZ1, the first correction amount is added to the average speed, and
the host vehicle M is decelerated from the current average
speed.
[0233] On the other hand, in the situation illustrated in part (b)
of FIG. 24, since the current deviation is within the first dead
zone DZ1, the first correction amount is decreased. In this case,
it becomes easy for the average speed derived by the first
calculation part 165 to be maintained without the deceleration
control being performed. Through such a process, it is possible to
suppress frequent deceleration when the host vehicle M has exceeded
the trajectory point K(0).
[0234] [Process of Changing Area of Dead Zone]
[0235] The proportional integral gain adjustment part 180 may
change an area size of the first dead zone DZ1 to be set for the
current deviation on the basis of an inter-vehicle distance between
the host vehicle M and one or both of the preceding vehicle
traveling immediately in front of the host vehicle M and the
subsequent vehicle traveling immediately behind the host vehicle M
among the nearby vehicles of which states are recognized by the
outside recognition part 142.
[0236] Further, the proportional gain adjustment part 181 may
change an area size of the second dead zone DZ2 to be set for the
future deviation on the basis of an inter-vehicle distance between
the host vehicle M and one or both of the preceding vehicle
traveling immediately in front of the host vehicle M and the
subsequent vehicle traveling immediately behind the host vehicle
M.
[0237] FIGS. 25 and 26 are figures illustrating a method of
changing the area size of the dead zone DZ.
[0238] As illustrated in FIG. 25, when the trajectory point K(i) is
in front of the host vehicle position P.sub.act(i), the
proportional integral gain adjustment part 180 or the proportional
gain adjustment part 181 increases a threshold value Th1 on the
positive side of the dead zone DZ, which are set by each of the
proportional integral gain adjustment part 180 and the proportional
gain adjustment part 181 as the inter-vehicle distance between the
host vehicle M and the subsequent vehicle increases, and decreases
the threshold value Th1 on the positive side as the inter-vehicle
distance between the host vehicle M and the subsequent vehicle
decreases. Accordingly, when the inter-vehicle distance between the
host vehicle M and the subsequent vehicle is small, the
acceleration and deceleration controller 164 can cause the
acceleration to be frequently performed by narrowing the dead zone
DZ in consideration of safety. In addition, when the inter-vehicle
distance between the host vehicle M and the subsequent vehicle is
great, the acceleration and deceleration controller 164 can cause
the frequency of the acceleration to be decreased by widening the
dead zone DZ.
[0239] Further, as illustrated in FIG. 26, when the trajectory
point K(i) is behind the host vehicle position P.sub.act(i), the
proportional integral gain adjustment part 180 or the proportional
gain adjustment part 181 increases a threshold value Th3 on the
negative side of the dead zone DZ, which are set by each of the
proportional integral gain adjustment part 180 and the proportional
gain adjustment part 181 as the inter-vehicle distance between the
host vehicle M and the preceding vehicle increases, and decreases
the threshold value Th3 on the negative side as the inter-vehicle
distance between the host vehicle M and the preceding vehicle
decreases. Accordingly, when the inter-vehicle distance between the
host vehicle M and the preceding vehicle is shortened, the
acceleration and deceleration controller 164 can cause the
deceleration to be frequently performed by narrowing the dead zone
DZ in consideration of safety. In addition, when the inter-vehicle
distance between the host vehicle M and the preceding vehicle is
increased, the acceleration and deceleration controller 164 can
cause the frequency of the deceleration to be decreased by widening
the dead zone DZ.
[0240] FIG. 27 is a flowchart showing an example of a flow of a
process of the acceleration and deceleration controller 164A in the
second embodiment. First, the first calculation part 165 extracts
trajectory points K(i) to K(i+n) that the host vehicle M should
reach until a time of n seconds elapses from a current time t.sub.i
from among the plurality of trajectory points K included in the
trajectory, and derives an average speed by dividing a route length
of the trajectory including these trajectory points K(i) to K(i+n)
by the time of n seconds (step S200).
[0241] Then, on the basis of the vehicle position P.sub.act(i)
recognized by the host vehicle position recognition part 140 and
the speed v and the acceleration .alpha. of the host vehicle M
detected by the vehicle sensor 60, the fourth calculation part 168
derives a predicted position P.sub.pre(i+1) that the host vehicle M
is predicted to reach at a time after one second has elapsed from
the current time t.sub.i (step S202).
[0242] Then, the subtractor 169 derives a current deviation
obtained by subtracting the host vehicle position P.sub.act(i) from
the trajectory point K(i) extracted by the second calculation part
166 (step S204). Then, the subtractor 170 derives a future
deviation obtained by subtracting the predicted position
P.sub.pre(i+1) derived by the fourth calculation part 168 from the
trajectory point K(i+1) extracted by the third calculation part 167
(step S206).
[0243] Then, the proportional integral gain adjustment part 180
determines whether or not the current deviation is within the first
dead zone DZ1 (step S208). When the current deviation is within the
first dead zone DZ1, the proportional integral gain adjustment part
180 decreases one or both of the proportional gain and the integral
gain in the proportional integral controller 171 (step S210). On
the other hand, when the current deviation is not within the first
dead zone DZ1, the proportional integral gain adjustment part 180
proceeds to a process of S212.
[0244] Then, the proportional integral controller 171 multiplies
the current deviation output by the subtractor 169 by the
predetermined proportional gain, multiplies the time integral value
of the current deviation by the predetermined integral gain, and
adds the resultant values to derive the first correction amount
(step S212). Then, the first output adjustment part 173 performs
filtering on the first correction amount (step S214).
[0245] Then, the proportional gain adjustment part 181 determines
whether the future deviation is within the second dead zone DZ2
(step S216). When the future deviation is within the second dead
zone DZ2, the proportional gain adjustment part 181 decreases the
proportional gain in the proportional controller 172 (step S218).
On the other hand, when the future deviation is not within the
second dead zone DZ2, the proportional gain adjustment part 181
proceeds to a process of S220.
[0246] Then, the proportional controller 172 multiplies the future
deviation output by the subtractor 170 by the predetermined
proportional gain to derive the second correction amount (step
S220). Then, the second output adjustment part 174 performs
filtering on the second correction amount (step S222).
[0247] Then, the third output adjustment part 175 performs
filtering on the third correction amount obtained by adding the
first correction amount and the second correction amount (step
S224). Then, the adder 177 adds the third correction amount
adjusted by the third output adjustment part 175 to the average
speed derived by the first calculation part 165 to output a
resultant value as a target speed of the host vehicle M for n
seconds from the current time t.sub.i (step S226). Accordingly, a
process of this flowchart ends.
[0248] According to the second embodiment described above, since
the dead zone DZ is set for any one or both of the future deviation
and the current deviation, frequent occurrence of the acceleration
and deceleration can be further suppressed. As a result, it is
possible to reduce the discomfort of the occupant while taking the
safety of the vehicle into consideration.
[0249] Further, according to the second embodiment, since the area
of the dead zone DZ is changed on the basis of the inter-distance
between the host vehicle and the preceding vehicle or the
subsequent vehicle, it is possible to efficiently suppress the
frequent occurrence of the acceleration and deceleration.
Third Embodiment
[0250] Hereinafter, a third embodiment will be described. The third
embodiment is different from the first and third embodiments in
that the output gain for the third correction amount is adjusted
when the speed of the host vehicle M is low.
[0251] Hereinafter, such a difference will be mainly described.
[0252] FIG. 28 is a figure illustrating an example of a
configuration of the acceleration and deceleration controller 164B
according to the third embodiment. The acceleration and
deceleration controller 164B includes, for example, a first
calculation part 165, a second calculation part 166, a third
calculation part 167, a fourth calculation part 168, subtractors
169 and 170, a proportional integral controller 171, a proportional
controller 172, a first output adjustment part 173, a second output
adjustment part 174, adders 176 and 177, a third gain adjustment
part 183, and a multiplier 184.
[0253] The third gain adjustment part 183 decreases an output gain
for adjusting the third correction amount obtained by adding the
first correction amount and the second correction amount as the
speed v of the host vehicle M decreases.
[0254] The multiplier 184 multiplies the output gain adjusted by
the third gain adjustment part 183 by the third correction amount
output by the adder 176, and outputs a result value to the adder
177.
[0255] FIG. 29 is a figure illustrating an example of change in the
output gain with respect to the speed v of the host vehicle M. As
illustrated in FIG. 29, when the speed v of the host vehicle M is
equal to or lower than a speed threshold value Vth, the output gain
decreases to 1 or smaller according to the decrease in the speed v.
Therefore, when the host vehicle M gradually decelerates and stops,
the third correction amount decreases, and therefore, the
occurrence of acceleration and deceleration is further
suppressed.
[0256] According to the third embodiment described above, since the
third correction amount is decreased as the speed of the host
vehicle M decreases, it is possible to suppress, for example,
frequent occurrence of acceleration and deceleration when the host
vehicle M stops.
[0257] Accordingly, it is possible to perform smooth stopping.
Further, according to the third embodiment, since the third
correction amount is increased as the speed of the host vehicle M
increases, it is possible to smoothly accelerate the host vehicle M
from a stopped state. As a result, it is possible to reduce
discomfort of the occupant.
Fourth Embodiment
[0258] Hereinafter, a fourth embodiment will be described. The
fourth embodiment is different from the first to third embodiments
in that a position serving as a reference (hereinafter referred to
as a calculation reference position) is set on the trajectory in a
predetermined case and acceleration and deceleration control is
performed on the basis of this calculation reference position.
Hereinafter, such a difference will be mainly described.
[0259] FIG. 30 is a figure illustrating an example of a
configuration of an acceleration and deceleration controller 164C
in the fourth embodiment. The acceleration and deceleration
controller 164C further includes, for example, a fifth calculation
part 185, in addition to the configuration of the acceleration and
deceleration controller 164 in the first embodiment described
above. The fifth calculation part 185 includes, for example, a
setting necessity determination part 185A and a calculation
reference position setting part 185B.
[0260] The setting necessity determination part 185A determines
whether or not it is necessary for the calculation reference
position setting part 185B to be described below to perform a
predetermined process.
[0261] For example, when the speed v of the host vehicle M is equal
to or lower than the speed threshold value Vth illustrated in FIG.
29 described above, the setting necessity determination part 185A
predicts that the current deviation or the future deviation
increases at the time of low-speed traveling, and causes the
reference position setting unit 185B to perform the predetermined
process.
[0262] Further, when a distance from the trajectory generated by
the trajectory generating part 146 or a distance from any
trajectory point K included in the trajectory to the host vehicle
position P.sub.act(i) at the current time t.sub.i is equal to or
greater than a predetermined distance, the setting necessity
determination part 185A may determine that the host vehicle M has
deviated from the trajectory and cause the calculation reference
position setting part 185B to perform the predetermined
process.
[0263] The calculation reference position setting part 185B sets
the calculation reference position VP(i) on the trajectory
generated by the trajectory generating part 146 on the basis of the
host vehicle position P.sub.act(i) at the current time t.sub.i.
[0264] FIG. 31 is a figure illustrating a method of setting the
calculation reference position VP(i).
[0265] As illustrated in FIG. 31, for example, the calculation
reference position setting part 185B sets a trajectory point K(i+1)
corresponding to a time t.sub.i+1 after one second has elapsed
after the current time t.sub.i as a provisional target position
P.sub.int.
[0266] The provisional target position P.sub.m, is a position that
is temporarily referred to as a target position at the time of
returning to the trajectory from the host vehicle position
P.sub.act(i).
[0267] The calculation reference position setting part 185B derives
a tangential line crossing a perpendicular line passing through the
host vehicle position P.sub.act(i) at a point of contact with the
trajectory among a plurality of tangential lines in contact with
the trajectory connecting the respective trajectory points K up to
the provisional target position P.sub.int using a smooth curve (for
example, a spline curve), and sets the calculation reference
position VP(i) at an intersection (contact) with the perpendicular
line on this tangential line.
[0268] The calculation reference position setting part 185B outputs
the set calculation reference position VP(i) to the first
calculation part 165, the second calculation part 166, and the
fourth calculation part 168.
[0269] The first calculation part 165 receives the set calculation
reference position VP(i) and treats the received calculation
reference position VP(i) as a trajectory point K(i) corresponding
to the current time t.sub.i, and derives an average speed by
dividing a route length of the trajectory from this calculation
reference position VP(i) to K(i+n) by a time corresponding to n
seconds.
[0270] In addition, the second calculation part 166 treats the
received calculation reference position VP(i) as an extracted
trajectory point K(i).
[0271] Further, the fourth calculation part 168 derives the
predicted position P.sub.pre(i+1) on the basis of the calculation
reference position VP(i).
[0272] Accordingly, even when the host vehicle M deviates from the
trajectory, the acceleration and deceleration controller 164C
projects a deviating position onto the trajectory. Therefore, it is
possible to derive the average speed, the current deviation, and
the future deviation in consideration of a positional deviation
with respect to the trajectory.
[0273] Further, the calculation reference position setting part
185B may set a trajectory point K(i+j) corresponding to a time
t.sub.i+j after j (j>1) seconds have elapsed from the current
time t.sub.i as the provisional target position P.sub.int.
[0274] In this case, the calculation reference position setting
part 185B, for example, may derive the tangential line crossing the
perpendicular line passing through the host vehicle position
P.sub.act(i) at the point of contact with the trajectory among the
plurality of tangential lines contacting the trajectory, and set a
trajectory point K closest to the intersection (contact) with the
perpendicular line on the tangential line as the calculation
reference position VP(i), instead of the above-described method of
setting the calculation reference position VP(i).
[0275] For example, in the example of FIG. 31 described above, when
the trajectory point K(i+2) has been set as the provisional target
position P.sub.int, the calculation reference position setting part
185B may set the trajectory point K(i) closer to the intersection
between the trajectory point K(i) and the trajectory point K(i+1)
as the calculation reference position VP(i).
[0276] [Process of Correcting Calculation Reference Position]
[0277] The calculation reference position setting part 185B may
correct the calculation reference position VP(i) set on the
trajectory on the basis of a positional relationship between the
calculation reference position VP(i) and the trajectory point K(i)
corresponding to the current time t.sub.i.
[0278] FIG. 32 is a figure schematically illustrating an example of
correction of the calculation reference position VP(i). For
example, when the calculation reference position VP(i)
corresponding to the host vehicle position P.sub.act(i) has been
set behind the trajectory point K(i) as illustrated in part (a) of
FIG. 32, the calculation reference position VP(i) may be changed to
the same position as the trajectory point K(i) or to a position in
front of the trajectory point K(i) as illustrated in part (b) of
FIG. 32. Accordingly, since the average speed or the current
deviation decreases, it is possible to suppress a sudden increase
in the target speed and prevent sudden acceleration of the host
vehicle M.
[0279] Further, the calculation reference position setting part
185B may correct the calculation reference position VP(i) set on
the trajectory on the basis of a positional relationship between
the calculation reference position VP(i) and the provisional target
position P.sub.int (for example, the trajectory point K(i+1) at the
next time).
[0280] FIG. 33 is a figure schematically illustrating another
example of the correction of the calculation reference position
VP(i). For example, a limit position LIM at which the calculation
reference position VP(i) can be set is set on the trajectory with
reference to the provisional target position P.sub.int, as
illustrated in part (a) of FIG. 33. For example, when the
calculation reference position VP(i) has been set behind the limit
position LIM, the calculation reference position setting part 185B
may change the calculation reference position VP(i) to the same
position as the limit position LIM or a position in front of the
limit position LIM, as illustrated in part (b) of FIG. 33.
[0281] FIG. 34 is a flowchart showing an example of a flow of a
process of the fifth calculation part 185 in the fourth
embodiment.
[0282] First, the setting necessity determination part 185A
determines whether or not the host vehicle M has deviated from the
trajectory (step S300).
[0283] When the host vehicle M has not deviated from the
trajectory, the setting necessity determination part 185A
determines whether or not the speed v of the host vehicle M is
equal to or lower than the speed threshold value Vth (step
S302).
[0284] When the speed v of the host vehicle M is not equal to or
lower than the speed threshold value Vth, the acceleration and
deceleration controller 164C ends the process of this
flowchart.
[0285] It should be noted that any one of the process of S300 and
the process of S302 may be omitted.
[0286] On the other hand, when the host vehicle M deviates from the
trajectory or when the speed v of the host vehicle M is equal to or
lower than the speed threshold value Vth, the calculation reference
position setting part 185B sets the calculation reference position
VP(i) on the trajectory generated by the trajectory generating part
146 on the basis of the host vehicle position P.sub.act(i) at the
current time t.sub.i (step S304).
[0287] Then, the calculation reference position setting part 185B
determines whether or not the set calculation reference position
VP(i) is located behind the trajectory point K(i) (step S306).
[0288] When the calculation reference position VP(i) is located
behind the trajectory point K(i), the calculation reference
position setting part 185B corrects the calculation reference
position VP(i) to be the same position as the trajectory point K(i)
or a position in front of the trajectory point K(i) (step
S308).
[0289] On the other hand, when the calculation reference position
VP(i) is not located behind the trajectory point K(i), the
calculation reference position setting part 185B ends the process
of this flowchart.
[0290] Accordingly, the first calculation part 165, the second
calculation part 166, and the fourth calculation part 168 perform
various calculation processes on the basis of the calculation
reference position VP(i) when the calculation reference position
VP(i) has been set by the calculation reference position setting
part 185B, and perform various calculation processes on the basis
of the host vehicle position P.sub.act(i) at the current time
t.sub.i when the calculation reference position VP(i) is not
set.
[0291] [Process after Setting of Calculation Reference Position
VP(i)] Hereinafter, a process of each calculation unit when the
calculation reference position VP(i) has been set by the
calculation reference position setting part 185B will be
described.
[0292] The first calculation part 165 derives an average speed by
dividing a route length of the trajectory from the calculation
reference position VP(i) to the trajectory point K(i+n) by the time
of n seconds. The second calculation part 166 treats the
calculation reference position VP(i) as the extracted trajectory
point K(i). Accordingly, the subtractor 169 derives, as the current
deviation, a deviation in the vehicle traveling direction obtained
by subtracting the calculation reference position VP(i) from the
trajectory point K(i) corresponding to the current time
t.sub.i.
[0293] On the basis of the calculation reference position VP(i) and
the speed v and the acceleration .alpha. of the host vehicle M
detected by the vehicle sensor 60, the fourth calculation part 168
derives a predicted position P.sub.pre(i+1) that the host vehicle M
is predicted to reach at a time after one second has elapsed from
the current time t.sub.i.
[0294] According to the fourth embodiment described above, the
fifth calculation part 185 sets the calculation reference position
VP(i) at the position closest to the position of the host vehicle M
recognized by the vehicle position recognition part 140 in the
trajectory generated by the trajectory generating part 146, and the
first calculation part 165 extracts the trajectory point K(i+n)
corresponding to the future time after a time of n seconds (the
first predetermined time) has elapsed from the current time t.sub.i
from among the plurality of trajectory points K included in the
trajectory and derives the target speed when the host vehicle M is
caused to travel along the trajectory on the basis of the length of
the trajectory from the calculation reference position VP(i) to the
trajectory point K(i+n). Therefore, for example, when the host
vehicle M has deviated from the trajectory or when the speed of the
host vehicle M becomes equal to or lower than the speed threshold
value Vth and the current deviation or the future deviation
increases, it is possible to accurately perform the speed control
of the vehicle along the trajectory.
Fifth Embodiment
[0295] Hereinafter, a fifth embodiment will be described. The fifth
embodiment is different from the first to fourth embodiments in
that a target speed to be output is limited without a process of
correcting the calculation reference position VP(i) being
performed. Hereinafter, such a difference will be mainly
described.
[0296] FIG. 35 is a figure illustrating an example of a
configuration of an acceleration and deceleration controller 164D
according to the fifth embodiment.
[0297] The acceleration and deceleration controller 164D further
includes, for example, a fourth gain adjustment part 186 and a
multiplier 187, in addition to the configuration of the
acceleration and deceleration controller 164 in the fourth
embodiment described above.
[0298] The fourth gain adjustment part 186 decreases the output
gain for adjusting the target speed output by the adder 177 as the
speed v of the host vehicle M decreases, instead of the calculation
reference position setting part 185B performing the correction of
the calculation reference position VP(i).
[0299] The multiplier 187 multiplies the output gain adjusted by
the fourth gain adjustment part 186 by the target speed output by
the adder 177, and outputs a resultant value. Accordingly, for
example, when the calculation reference position VP(i) is set
behind the trajectory point K(i) and the distance from the
calculation reference position VP(i) to the trajectory point K(i+n)
after n seconds becomes longer than an actual travel distance, it
is possible to suppress unnecessary acceleration of the host
vehicle M.
Sixth Embodiment
[0300] Hereinafter, a sixth embodiment will be described. The sixth
embodiment is different from the first to fifth embodiments in that
when the host vehicle M has deviated from the trajectory or when
the speed v of the host vehicle M has become equal to or lower than
the speed threshold value Vth, an event in the action plan is
changed or the automated driving mode to be executed is switched to
another automated driving mode or the manual driving mode.
Hereinafter, such a difference will be mainly described.
[0301] When the host vehicle M has deviated from the trajectory or
when the speed v of the host vehicle M has become equal to or lower
than the speed threshold value Vth, the automated driving mode
controller 130 in the sixth embodiment sets the automated driving
mode to be currently executed to a mode with a lower degree of
automated driving.
[0302] For example, when mode A in which there is no surroundings
monitoring obligation is being executed, the automated driving mode
controller 130 changes the automated driving mode to be executed to
mode B or mode C.
[0303] Accordingly, since the vehicle occupant has the surroundings
monitoring obligation, it is possible to prompt the attention of
the vehicle occupant to be directed to the surroundings of the host
vehicle M. As a result, the vehicle occupant can recognize that the
host vehicle M is traveling while deviating from the trajectory,
and can drive the host vehicle M manually by appropriately
operating the changeover switch 80.
[0304] Further, the action plan generating part 144 in the sixth
embodiment may change the current event to an event in which there
is no (or less) need for acceleration and deceleration control,
instead of the above event change, when the host vehicle M has
deviated from the trajectory or when the speed v of the host
vehicle M has become equal to or lower than the speed threshold
value Vth.
[0305] For example, when the current event is the lane change
event, the action plan generating part 144 may change the lane
change event to the lane keeping event or the like. In this case, a
travel aspect during the lane keeping event is determined to be
constant speed traveling in which there is no acceleration and
deceleration. Accordingly, it is easy for the automated driving
mode to be maintained even in a situation in which the deviation
increases.
[0306] Further, the switching controller 150 in the sixth
embodiment can delegate a right to operate the host vehicle M to
the vehicle occupant by switching the driving mode from the
automated driving mode to the manual driving mode when the host
vehicle M has deviated from the trajectory or when the speed v of
the host vehicle M has become equal to or lower than the speed
threshold value Vth, independently of an operation of the
changeover switch 80.
[0307] Although the modes for carrying out the present invention
have been described above by way of embodiments, the present
invention is not limited to the embodiments at all, and various
modifications and substitutions may be made without departing from
the scope of the present invention.
REFERENCE SIGNS LIST
[0308] 20 Finder [0309] 30 Radar [0310] 40 Camera [0311] DD
Detection device [0312] 50 Navigation device [0313] 55
Communication device [0314] 60 Vehicle sensor [0315] 62 Display
device [0316] 64 Speaker [0317] 70 Operation device [0318] 72
Operation detection Sensor [0319] 80 Changeover switch [0320] 100
Vehicle control system [0321] 110 Target lane determination part
[0322] 120 Automated driving controller [0323] 130 Automated
driving mode controller [0324] 140 Host vehicle position
recognition part [0325] 142 Outside recognition part [0326] 144
Action plan generating part [0327] 146 Trajectory generating part
[0328] 146A Traveling aspect determination unit [0329] 146B
Trajectory candidate generation part [0330] 146C Evaluation and
selection part [0331] 150 Switching controller [0332] 160 Travel
controller [0333] 162 Steering controller [0334] 164 Acceleration
and deceleration controller [0335] 165 First calculation part
[0336] 166 Second calculation part [0337] 167 Third calculation
part [0338] 168 Fourth calculation part [0339] 169, 170 Subtractor
[0340] 171 Proportional integral controller [0341] 172 Proportional
controller [0342] 173 First output adjustment part [0343] 174
Second output adjustment part [0344] 175 Third output adjustment
part [0345] 176, 177 Adder [0346] 185 Fifth calculation part [0347]
185A setting necessity determination part [0348] 185B calculation
reference position setting part [0349] 190 Storage [0350] 200
Driving force output device [0351] 210 Steering device [0352] 220
Brake device [0353] M Host vehicle
* * * * *